Racket stringing device



' Nov. 11, 1941. P. MINI-:CK RACKET STRINGING- DEVICE 4 sheets-sheet 1 Filed June 14, 1940 IN1/Emme. PQUL mmscrc- FIT k @fw-UQ HTTURNE?.

2,262@ lof Nw. N, imi. P, MNEcK RACKET STRINGING DEVICE 4 sheets-sheet s Filed June 14, 1940 l INYENTDE- PHUL PIINE'E'K BTI-7. L @uw P. MHNECK RACKET SITRINGING DEVICE Nav. 11, 1941.

4 Sheets-Shree?l 4 Filed June 14, 1940 Patented Nov. l1, 1941 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to improvements in devices for Stringing rackets, such as tennis rackets, badminton rackets, and other such rackets.

The principal object of this invention is to provide means whereby the racket may be quickly strung in such a manner that all the strings of the racket will be under equal tension.

A further object of the invention is to provide a device wherein the racket frame will not be warped due to the tensioning of the strings.

A further object of the invention is to provide means for accommodating rackets of different sizes and to further provide means for locating the center of the racket-that is, the part being strung directly over the center of the table or the pivotal axis of the device.

A still further object of the invention is to provide means for employing the same clamps for holding the longitudinal stringsthat is, the strings extending from the head of the racket toward the handle of the racket, and to also hold the horizontal strings, which are placed at a right angle to the longitudinal strings, and to so shift these clamps without loosening the racket frame from the supporting Vises.

Other objects and advantages will be apparent during the course of the following description.

`In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same:

Fig. 1 is a top plan View of my device;

Fig. 2 is a fragmentary cross sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is a side elevation of Fig. 1;

Fig. 4 is a View similar to Fig. 1 on a reduced scale and showing a racket positioned on the device and partly strung;

Figs. 5, 6, 7, and 8 arc diagrammatic views, showing the steps in the lacing of the longitudinal strings;

Fig. 9 is a fragmentary cross sectional View, showing the manner in which the frame is engaged in one of the vise clamps;

Fig. 10` is a side elevation of one of the string clamps, illustrating the manner in which the string is engaged by the clamp;

Fig. 11` is a fragmentary top plan view of a portion of the racket, showing the manner in which the strings are interwoven and the relation of the clamp thereto; and

Fig, l2' is a diagrammatic view, showing the employment of a single clamp wheny lacing the horizontal strings.

Tennis rackets and other such rackets are, in

most instances, constructed of wood bent in oval form and provided with a handle integrally f formed therewith. The oval portion. is drilled so as to receive therethrough a gut which is threaded back and forth through the holes to` forman interlaced web often referred to a the strings of the racket.

It has been common practice to fasten one one of the gut in one of the holes of the racket, to pull the gut as tightlyv as possible by main force, and to insert a plug in one of the holes in which the gut is being pulled so as to hold the gut temporarily untilA another lacing and pulling operationA takes place; It is obviousthat in this manner the individual strings will all be of uneven tension, as it is a physical impossibility for a person to manually pull every string to the same tension. Therefore, no two rackets which are hand strung will conform equally one with .the other.

Applicantchas, therefore, produced'a machinev wherein the strings may be threaded and tensioned evenly through the entire racket and in such a manner that when the cross strings vare laced and tensioned, all the strings, both horizontal and longitudinal, will have an equal tension, and `due to the weaving will all have the same general wavy formation, which is not possible except when all strings are equally tensioned. In the hand weaving of a racket, the longitudinal strings may be straight while the horizontal strings will be waved as they are interlaced with the longitudinal strings.

In the accompanying drawings wherein rfor the purpose of illustration is shown a preferred embodimentof my invention, the numeral 5 `desgnates a base having a horizontal arm 6. Mounted on this base is a table 'I which is rectangular in shape and has formed at each corner thereof upstanding lugs 8, 9, I'I, and I2. The distance between the adjacent faces of all of these lugs is equal, which permits the slide rods I3 and I4 to be moved from the full line position of Fig. 1 to the dotted line position of this figure, which dotted line positions are designated by the numerals I5 and I'I. Slidable on. the rods I3 andy I4 is a pair of carriers I8 and I9,- respectively, and between each pair arecross rods 27|, and upon each of these cross rods is positioned a clamp 22 (see Fig. 10). These clamps are tightened through themedium of a hand wheel 23. In order to` hold the slide rods I3 and I4 in either of their adjusted positions, I employ slip pins I5 which pass through the lugs and into the ends of the slide rods (see Figs. 1 and 2). The table 1 is pivoted to the base 5 by a pivot bolt 24, and a locking hand wheel is provided at 26 so that the table may be rotated on the base and locked in any desired position.

The construction thus far described results in a table rotatable on a base and having mounted thereon a pair of clamps, which may be positioned parallel to any of the four sides of the table, and which clamps may be slid along the cross rods from which they are supported; and the cross rods in turn may be slid upon their slide rods, which construction enables the clamps to be moved to any desired position above the table and to be parallel to two of the edges.

In order to support a racketabove the table,

I provide racket supports 21 and 28 which are slidably held to the table by hand screws 219 and 3|, respectively, and are guided upon the base by ribs 32. Each one of these racket supports carries at its upper end a vise-like arrangement which is tightened by a thumb screw, as shown at 33 and 34. The upper plates of the vises are shown at 36 and 31, and the lower plate of each vise is formed by a portion of the related racket support. Thus, when a racket, shown at` A, is

mounted on the racket supports and clamped by the vises, as shown in Fig. 3, the hand screws 29 and 3l may be loosened and the racket suplports may be moved in unison so that the center racket being strung, thus quickly accommodatf ing 'it to a large tennis racket or a small'badminton racket.

- .Mounted on the support 38 is ahydraulic cylinder 39 connected to a yoke 4I formed integral with a tension arm 42, which is connected to the support 38 by parallel links 43 and 44 (see Figs. 1 and 3). Positioned on the tension arm is a tension ydrum 46, which is rotated through the me-` dium of a key, shown in dotted lines at 41 (see Fig. 1).

ratchet 49 secured thereto, or the ratchet may be thrown out of engagement through the medium K of a pin 5I. A gauge 52 is connectedto the hy draulic cylinder 39 so as to register the pressure in the cylinder. i i

Thek manner of stringing a racket with my device is asfollows: i Y

First, a long length of gut is -looped upon itself so that the two ends are even. These two ends are now threaded into fthe head end of the racket-that is, the end away from thehandlegand the two ends are now passed across the opening of the racket and into the two openings adjacent the handle. The strings are arranged one on each side ofthe medial line of the racket, as illustrated in Fig. 5. One of the clamps 22 is now placed in the position B and tightened. This will hold one portion of the. gut while the other portion is wrapped around the tension drum 46 and the ten- This drum may be prevented from rotating in one direction bya dog 4B engaging a sion drum rotated by the key 41 so as to cause a pull on the gut, which pull will in turn be transmitted through the tension arm to the hydraulic cylinder 39, and the presssure created therein will register on the gauge 52. The ratchet 49 and dog 48 may be used, if desired, to keep the tension on the gut, or the tension may be held through the use of the key 41. The second clamp is now moved so as to engage the tensioned gut or string and clamped at the point C (see Fig. 6). The gut is now again threaded through the racket back toward the head end, and the table is swung around so that the head end is adjacent the tension drum. The gut is now wound around the tension drum, and the same rotated to again place tension on the newly threaded string, as shown at Dl (see Fig. 7). The clamp now in the position C' of Figs. 6 and '1 is loosened and moved Von its rod 2| to the position El of Fig 8; and it is,

of course, understood that each time the clamp is tightened, it will hold :the gut under the tension which was registered on the gauge. This operation is repeated until a few strings have been threaded on one side of the medial line of the racket. Then the same operation is repeated on the opposite side of the medial line of the racket, and, in this way, both sides are gradually strung with the gut, thus placing the same tension on both sides of the racket frame.

When all the longitudinal strings have been placed, the ends are fastened, and as a result of the Stringing operation thus far described, all the longitudinal strings will have the same tension. It might be here mentioned that the tension of the longitudinal strings, as shown on the gauge, is less than the tension of the horizontal strings, the reason for which will be later explained.

In. order to apply the horizontal'strings, I rst transfer the slide rods I 3 and I4 from the full line positions of Fig. 1 to the dotted line positions of Fig. 1.l One of the sets of carriers and its cross rod and clamp is now removed, as one clamp is sufficient in most instances. One end of the horizontal string is fastened to the frame of the racket and weaved through the longitudinal strings, as shown in Fig. 1l. The free end of the gut is then passed through the frame and around the tension drum, which is then rotated to place a tension upon the string. rIhe clamp is now moved to engage the gut at a point near the tension drum and tightened, as before described. The gut is now released from the drum and rethreaded through the frame of the racket so as to produce the second horizontal string. The table is rotated and the gut again wound around the tension drum and tightened, as previously described. The clamp is now released and reengaged with the new horizontal string and at a point in the racket closest to the tension drum. This operation is illustrated in Fig. 12 where the clamp is shown at F and is ready to be released and again engaged with the string at the point G.

This operation is repeated until the stringing ofthe racket is completed, and it is to be here noted that the tension `on the cross strings is applied under greater pressure so as to cause the flexing of the strings at the points of crossing, as shown in Fig. 10. This flexing of the longitudinal strings, which were previously placed at a lower tension, results in increasing their tension so that their tension becomes equal to the tension of the horizontal strings. Consequently, the entire frame of the racket is under equal tension and will not, therefore, be pulled out of shape, as is commonly .a fault With rackets that are hand strung.

It is to be understood that the form of my invention herewith shown and described is to be taken as a preferred example of the sa-me and that various changes relative to the material, size, shape and arrangement of parts may be resorted to Without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. In a racket Stringing device, a rotatable racket support, a tensioning device in alignment with a racket positioned on said support and comprising a laterally adjustably supported hydraulic cylinder, a tensioning drum movably mounted adjacent said cylinder, a piston mounted in said cylinder and connected to said drum, and registering means operated by the movement of said piston in said cylinder when a string reeved through said racket is tensioned by the rotation of said drum.

2. In a racket Stringing device, a base, a horizontally disposed arm carried by said base, means for supporting a racket above said base and said arm, a support adjustably carried by said arm,

a hydraulic cylinder carried by said support, a tensioning arm movably supported on said support and connected to said cylinder, a rotatable drum carried by said tensioning arm, and indicator means connected to said hydraulic cylinder whereby the pull of a string connected to said racket and rotated about said drum will be registered on said indicating device.

3. In a racket stringing device, a base, a horizontally disposed arm carried by said base, means for supporting a racket above said base and comprising a pair of supports which may be simultaneously moved with respect to said base when said supports have a racket secured thereto, a support adiustably carried on said arm, a hydraulio cylinder carried by said support, a tensioning arm movably supported on said support and connected to said cylinder, a rotatable drum carried by said tensioning arm, and indicator means connected to said hydraulic cylinder, whereby the pull of a string connected to said racket and rotated about said drum will be registered on the indicating device.

PAUL MINECK. 

